English
Related papers

Related papers: Non LTE radiation processes: application to the so…

200 papers

We study the formation of O I and OH spectral lines in three-dimensional hydrodynamic models of the solar photosphere. The line source function of the O I 777 nm triplet is allowed to depart from local thermodynamic equilibrium (LTE),…

Astrophysics · Physics 2007-05-23 Dan Kiselman , Åke Nordlund

We analyse a simple model of the heat transfer to and from a small satellite orbiting round a solar system planet. Our approach considers the satellite isothermal, with external heat input from the environment and from internal energy…

Space Physics · Physics 2009-09-25 Jose Gaite , Angel Sanz-Andrés , Isabel Pérez-Grande

The characteristic rapid rise and decline at optical wavelengths of a kilonova is the product of the low ejecta mass ($\lesssim 0.05 M_\odot$) and high ejecta velocity ($\gtrsim 0.1$c). We show that, even at very early times ($\lesssim 2$…

High Energy Astrophysical Phenomena · Physics 2025-08-28 Daniel Brethauer , Daniel Kasen , Raffaella Margutti , Ryan Chornock

Methods of calculation of NLTE model atmosphere are discussed. The NLTE trace element procedure is compared with the full NLTE model atmosphere calculation. Differences between LTE and NLTE atmosphere modeling are evaluated. The ways of…

Solar and Stellar Astrophysics · Physics 2016-07-27 Jiří Kubát , Brankica Šurlan

Thermal non-equilibrium (TNE) is believed to be a potentially important process in understanding some properties of the magnetically closed solar corona. Through one-dimensional hydrodynamic models, this paper addresses the importance of…

Solar and Stellar Astrophysics · Physics 2019-05-29 C. D. Johnston , P. J. Cargill , P. Antolin , A. W. Hood , I. De Moortel , S. J. Bradshaw

The limits of linear electrodynamics are reviewed, and possible directions of nonlinear extension are explored. The central theme is that the qualitative character of the empirical successes of quantum electrodynamics must be used as a…

High Energy Physics - Theory · Physics 2007-05-23 David Delphenich

The solar chromosphere is a region where radiation plays a critical role in energy transfer and interacts strongly with the plasma. In this layer, strong spectral lines, such as the Lyman lines, contribute significantly to radiative energy…

Solar and Stellar Astrophysics · Physics 2026-02-10 W. Ruan , D. Przybylski , R. Cameron , S. K. Solanki

Ultraviolet over-ionisation of iron atoms in the solar atmosphere leads to deviations in their level populations from the Saha-Boltzmann statistics. This causes their line profiles to form in Non-Local Thermodynamic Equilibrium (NLTE)…

Solar and Stellar Astrophysics · Physics 2020-01-29 H. N. Smitha , R. Holzreuter , M. van Noort , S. K. Solanki

We investigated the reliability of our silicon atomic model and the influence of non-local thermodynamical equilibrium (NLTE) on the formation of neutral silicon (Si I) lines in the near-infrared (near-IR) H-band. We derived the…

Solar and Stellar Astrophysics · Physics 2016-10-20 Junbo Zhang , Jianrong Shi , Kaike Pan , Carlos Allende Prieto , Chao Liu

The copper abundances of 29 metal-poor stars are determined based on the high resolution, high signal-to-noise ratio spectra from the UVES spectragraph at the ESO VLT telescope. Our sample consists of the stars of the Galactic halo, thick-…

Solar and Stellar Astrophysics · Physics 2018-08-08 J. R. Shi , H. L. Yan , Z. M. Zhou , G. Zhao

The non-local thermodynamic equilibrium (NLTE) line formation of neutral boron in the atmospheres of cool stars are investigated. Our results confirm that NLTE effects for the B I resonance lines, which are due to a combination of…

Solar and Stellar Astrophysics · Physics 2010-04-07 Kefeng Tan , Jianrong Shi , Gang Zhao

Accurately known stellar lithium abundances may be used to shed light on a variety of astrophysical phenomena such as Big Bang nucleosynthesis, radial migration, ages of stars and stellar clusters, and planet engulfment events. We present a…

Solar and Stellar Astrophysics · Physics 2020-10-30 E. Wang , T. Nordlander , M. Asplund , A. M. Amarsi , K. Lind , Y. Zhou

Magnetic flux emergence has been shown to be a key mechanism for unleashing a wide variety of solar phenomena. However, there are still open questions concerning the rise of the magnetized plasma through the atmosphere, mainly in the…

Solar and Stellar Astrophysics · Physics 2020-01-15 D. Nóbrega-Siverio , F. Moreno-Insertis , J. Martínez-Sykora , M. Carlsson , M. Szydlarski

Solar Coronal Heating is a Nonlinear Quantum Mechanical Phenomenon. Corona is a powerful source of X-rays and ionisations & emissions of such radiations are quantum mechanical and levels are highly unstable to order of femto-seconds. A…

Solar and Stellar Astrophysics · Physics 2019-03-28 Antony Soosaleon

We reach a thermodynamic interpretation of CODET model and its prediction to electrons density and temperature grounded on the physics of hydro magnetism in global equilibrium. The thermodynamic interpretation finds consistency with the…

Solar and Stellar Astrophysics · Physics 2020-05-19 Daniel B. Berdichevsky , Jenny M. Rodríguez Gómez , Luis E. Vieira , Allison Dal Lago

Supernovae, with their diversity of compositions, velocities, envelope masses, and interactions are good testing grounds for probing the importance of NLTE in expanding atmospheres. In addition to treating H, He, Li I, O I, Ne I, Na I, and…

Astrophysics · Physics 2007-05-23 E. Baron , P. H. Hauschildt , P. Nugent , D. Branch

The study of non-equilibrium physics from the perspective of the quantum limits of thermodynamics and fluctuation relations can be experimentally addressed with linear optical systems. We discuss recent experimental investigations in this…

The solar chromosphere is very dynamic, due to the presence of large amplitude hydrodynamic waves. Their propagation is affected by NLTE radiative transport in strong spectral lines, which can in turn be used to diagnose the dynamics of the…

Astrophysics · Physics 2009-11-13 R. Hammer , P. Ulmschneider

We constructed a comprehensive model atom for C\ione\ -- C\ii\ using the most up-to-date atomic data available and evaluated the non-local thermodynamic equilibrium (NLTE) line formation for C\ione\ and C\ii\ in classical 1D models…

Solar and Stellar Astrophysics · Physics 2016-08-17 S. A. Alexeeva , T. A. Ryabchikova , L. I. Mashonkina

Context. A derivation of a generalized sqrt(epsilon)-law for nonthermal collisional rates of excitation by charged perturbers is presented. Aims. Aim of this paper is to find a more general analytical expression for a surface value of the…

Astrophysics · Physics 2009-11-16 Jiri Stepan , Veronique Bommier